Ambient Air Purification Device, Road Vehicle Having an Ambient Air Purification Device and Filter Element

ABSTRACT

An ambient air purification device for a road vehicle for removing dust, particulate matter, and/or gases from ambient air has one or more filter elements. The ambient air purification device is attachable in an external region to a vehicle rear of the road vehicle by a releasable coupling. The ambient air purification device has at least one mating coupling of the releasable coupling, wherein the at least one mating coupling is coupled to a vehicle-side coupling component of the releasable coupling. A road vehicle provided with such an ambient air purification device is provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of international application No. PCT/EP2018/051226 having an international filing date of 18 Jan. 2018 and designating the United States, the international application claiming a priority date of 18 Jan. 2017 based on prior filed German patent application No. 10 2017 000 412.9, a priority date of 22 May 2017 based on prior filed German patent application No. 10 2017 004 864.9, and a priority date of 19 Jul. 2017 based on prior filed German patent application No. 10 2017 006 794.5, the entire contents of the aforesaid international application and the aforesaid German patent applications being incorporated herein by reference.

BACKGROUND OF THE INVENTION

The invention relates to an ambient air purification device that is embodied in particular for separating dusts, in particular particulate matter, and/or gases. Moreover, the present invention relates to a road vehicle, in particular but not limited thereto, a passenger car or truck, in particular a light truck, that comprises an ambient air purification device, and to a filter element therefor.

Due to the progressing urbanization, there is the problem that, primarily in metropolitan areas, limit values for particulate matter and/or gases, such as ozone, NO_(x), CO, in the ambient air may be exceeded by several orders of magnitudes by industrial pollution, the road traffic, and private fireplaces, primarily in adverse weather conditions (no rain, inversion, minimal wind speed, no air exchange between air layers).

One approach already documented in the prior art is to utilize the already existing vehicles (for example, approximately 44 millions in Germany in the year 2014, more than 106 millions in China) as mobile ambient air purifiers.

In DE 20 2006 019 335 U1, a particulate matter suction device for a vehicle is described which is arranged at the undercarriage of the vehicle and is used for filtration of the air flow that is to be introduced into the interior of the vehicle. The particulate matter suction device comprises a blower in a housing that draws in an air flow from the ambient into the housing and supplies it to a filter element. For assisting in the supply of the air mass flow into the particulate matter suction device, a projecting flow deflector is arranged at the housing.

Moreover, JP H04297341 A1 discloses a suction device which is mounted at a truck. Here, between the driver=s cabin and the box body, an intake hood is provided through which the air to be purified is supplied to a purification device that is arranged along the longitudinal vehicle axis in a region below the box body. The purification device comprises a blower in order to achieve flow under as many operating conditions as possible, even when parked.

WO 2004/080740 A1 discloses a motor vehicle with an external air filter which is arranged in a region affected by the rear wheels of the vehicle, for example, in a wheel well liner or as a part of a rear mud flap. Disadvantageously, noteworthy filter surfaces for filtering a meaningful quantity of air can hardly be provided at the installation spaces described therein.

Moreover, passive flow-through systems are disclosed in WO 2005/094969 A1 (arrangement at the sidewall of a vehicle) and US 2006/0107636 A1 (arrangement on the roof).

DE 20 2005 005 673 U1 discloses a passive ambient air purification device that is arranged below a rear bumper face bar and whose filter element is flowed through vertically so that, at least at the inflow side, a hood must be provided which produces an unnecessary pressure loss.

WO 2009/105800 A1 discloses an ambient air purification device which is arranged either on the roof of a truck or in the region of the vehicle front wherein vehicle parts are positioned within the flow path downstream of the filter, respectively.

The solutions known from the prior art are disadvantageously permanently fastened to the vehicle. However, the aforementioned weather conditions with bad air quality, in particular in regard to particle load and harmful gas load, in particular increased particulate matter load, exist mostly only for a limited period of time. It would therefore be desirable to be able to furnish a road vehicle only selectively with the ambient air purification device.

SUMMARY OF THE INVENTION

The invention has therefore the object to overcome the aforementioned disadvantages of the prior art, in particular the object resides in providing an ambient air purification device which is distinguished in that it can be easily, i.e., even by a technically unskilled end user, and quickly attached to a road vehicle and removed again therefrom.

This object is solved by an ambient air purification according to the invention for a road vehicle that is in particular embodied for removing dusts, in particular particulate matter, and/or gases from the ambient air. It comprises at least one filter element and can be arranged in an external region of the road vehicle. The ambient air purification device is configured to be attached by means of a releasable coupling to a rear of a vehicle, wherein the ambient air purification device comprises at least one mating coupling corresponding to a vehicle-side coupling component.

This object is further solved by a road vehicle, in particular passenger car or truck, in particular light truck, in particular driven by an internal combustion engine and/or electric drive, comprising an ambient air purification device that in particular is configured for removing dust, in particular particulate matter, and/or gases from the ambient air, wherein the ambient air purification device comprises at least one filter element and is arranged in an external region of the road vehicle. The ambient air purification device is an ambient air purification device as described above which is fastened at the vehicle rear by means of a releasable coupling, wherein the road vehicle comprises a vehicle-side coupling component which is releasably connected with the corresponding mating coupling of the ambient air purification device.

The object is further solved by a filter element of the ambient air purification device according to the invention.

Such a selective installation of an ambient air purification device at a road vehicle is of particular interest when, in times of high pollutant load, bans on driving exist in affected regions for road vehicles having net emissions that are too high. In such a scenario, the end user could circumvent such a ban on driving by selectively attaching the ambient air purification device to his vehicle.

Such an attachment of the ambient air purification device at the rear of the vehicle has several decisive advantages: Firstly, a mechanically strongly loadable element exists in the form of a vehicle-side trailer coupling component; moreover, mounting/demounting is quick and easy due to a single force application point; moreover, due to the spacing of the coupling head from the car body there is no risk that the car body becomes damaged upon mounting/demounting.

The term Afilter element@ is to be understood such that it can be embodied as one piece or as multiple parts and may comprise in particular a plurality of filter units, in particular filter bellows and/or filter pockets. Also, a plurality of sub filter elements can be provided which are joined to a filter element.

In a particularly preferred embodiment, the mating coupling of the ambient air purification device can comprise or consist of a trailer coupling. In particular, the trailer coupling can be a mating coupling for a vehicle-side ball mount coupling, which represents the standard in the field of passenger cars. Alternatively or additionally, the mating coupling can also comprise a hatchback carrier device which may comprises in particular at least one fastening element, in particular a hook element, a magnetic mating coupling element and/or a suction cup, that is connectable with a vehicle door or vehicle lid, in particular a hatchback. Such fastening elements are known in the field of rear carriers, in particular bicycle carriers, and can be also used, due to their attachment at the hatchback, in vehicles without vehicle-side trailer coupling component. In principle, they are as easily and quickly mountable as a system that uses the trailer coupling. Advantageously, an attachment of the ambient air purification device, for example, by means of a suitable carrier system, can be realized at the hatchback such that the latter can still be opened with attached ambient air purification device. Optionally, in such a case, stronger gas springs and/or a (linear) drive-supported opening mechanism of the hatchback is advantageous.

By means of the magnetic fastening element, the ambient air purification device according to the invention can be secured at a ferro-magnetic car body component of the road vehicle. A magnetic attachment is advantageously possible particularly quickly; that even heavier loads can be secured reliably thereby has been demonstrated, for example, by magnetic ski carriers. Moreover, the fastening element can comprise at least one suction cup; even suction cups are suitable for safely attaching an ambient air purification device according to the invention. The term Avehicle-side coupling component@ in accordance with the last mentioned embodiments is to be interpreted broadly; for example, in case of a magnetic mating coupling element a magnetic car body section functions as a vehicle-side coupling component while in case of a suction cup as a mating coupling element any surface section of the car body, which has a sufficiently minimal roughness, can serve as a vehicle-side coupling component.

The afore described arrangement of the ambient air purification device at a trailer coupling provides the advantage that it can be attached and removed by the end user with a few manipulations; it is reversible. When the ambient air is momentarily not loaded with particulate matter and/or harmful gases and/or for traveling in low-load regions, on vacation trips etc., he can simply decouple the ambient air purification device while he can simply selectively attach the ambient air purification device again for traveling in highly loaded metropolitan areas and/or zones with bans on driving for high-emission vehicles.

According to a further embodiment, it is possible that the ambient air purification device comprises at least one receiving housing in which the at least one filter element is received. The receiving housing comprises at least one inlet opening and one outlet opening and is in particular connectable by means of the mating coupling to the road vehicle. The receiving housing, for example, can comprise a force-absorbing frame, which absorbs the operating forces, as well as a covering hood, which may be embodied to be separately detachable in order to be able to exchange the at least one filter element as easily as possible. The inlet opening(s) can be provided in a mounted state in the intended travel direction at the front and/or laterally, at the top or bottom at the receiving housing. In case of a lateral arrangement at an upper, lower or lateral wall, an arrangement of the inlet opening(s) at the forward region of these walls, viewed in the travel direction, is preferred in order to be able to guide the flow with minimal constructive expenditure inside the ambient air purification device. The lateral arrangement is in particular advantageous in mounting positions which are not directly exposed to the oncoming wind when driving, such as behind the vehicle. Moreover, it is possible and expedient that the ambient air purification device comprises at least two filter elements which in transverse vehicle direction are arranged adjacent to each other, in particular at a predetermined spacing between them.

The receiving housing can comprise a titanium dioxide-containing coating at its exterior side for photo-catalytic oxidation of NO2 to NO3.

Between the filter elements, a spacing can be also provided which, for example, may serve for passing through cables, hydraulic lines and the like. Moreover, it can be expedient to employ two separate filter elements because one large filter element that extends across a significant portion of the vehicle width is difficult to produce and moreover has a great weight, which makes the exchange more difficult. In an embodiment with two or more separate filter elements, it can moreover be provided that each filter element comprises its own housing.

According to yet another embodiment, the ambient air purification device can comprise at least one flow deflector that is preferably provided at an edge of the ambient air purification device extending in transverse vehicle direction, preferably in the travel direction to the rear. By means of such an arrangement of the flow deflector, it can be achieved advantageously that emissions of vehicle-associated emission sources, such as brakes, exhaust gases and tire abrasion, can be supplied in a targeted fashion to the ambient air purification device. Of course, the invention is not limited to an arrangement of the flow deflector at the aforementioned mounting position; other mounting positions such as at a leading, outer or lateral edge extending in vertical vehicle direction are also possible. By means of the flow deflector advantageously an impact pressure upstream of the filter element of the ambient air purification device can be increased so that, in a mounting state, an inflow by means of the travel speed can contribute to the flow. Furthermore, it can be provided that such flow deflectors are arranged at the leading lateral edges (vertical) of the ambient air purification device as well as at the lower transverse edge (horizontal), wherein it is particularly advantageous when the lower flow deflector extends as close as possible down to the road surface.

Alternatively or in addition, flow deflector(s) can be provided at a flank of the vehicle where the ambient air purification device according to the invention is mounted, for example, in a longitudinal region that is between the rear axle and the front axle. In this way, a tunnel effect of the undercurrent of the vehicle can be achieved. The flank-side flow deflectors can also be embodied as shroud parts/planking parts or as a part of a lateral underride protection.

The flow deflector can be a flow deflector plate that is preferably positioned tilted at an angle relative to the vertical vehicle direction, longitudinal axis or transverse axis. The flow deflector plate can be embodied, for example, as a flow guide plate or shaped rubber part, rubber profile and/or rubber lip; other materials, in particular synthetic materials, are of course also possible, assuming a sufficient mechanical resilience. Optionally, also a switching function of a flow deflector can be provided whereby this may be an adjustable flow guide plate that can be adjusted between various positions in order to influence the air flow guiding action. The flow guide plate is adjustable between an inoperative position and an operative position wherein, in the operative position, the air flow is guided to the filter element in the particulate matter suction device. In the inoperative position, however, the air supply to the filter element can be stopped.

Preferably, the at least one flow deflector can be designed such that in traveling operation the local air pressure in the inlet region of the ambient air purification device is increased and/or is lowered in the outlet region. In this way, the separation performance per travel distance can be improved and passive flow proportions can be achieved (driven by impact pressure).

According to an advantageous further embodiment, it can be provided that the ambient air purification device comprises at least one pre- or coarse separator which is upstream in flow direction, viewed in travel direction, of the at least one filter element, in particular a separator grid, separator net, baffle plates and/or a preseparator nonwoven. Moreover, it can be provided, for example, that the pre- or coarse separator, in particular the separator grid, is connected with the at least one flow deflector. The coarse separator, in particular the separator grid, is provided to prevent that foreign matter can pass into the ambient air purification device and damage the filter element. The separator grid can be designed for this purpose as a coarse mesh and can have a mesh size of 1 mm to 4 mm, preferably 6 mm to 8 mm so that only a negligible small additional pressure loss is generated by it. Such grids are available extremely inexpensively, for example, as aluminum expanded metal. In a further embodiment, it can however also be provided that the coarse separator fulfills a filtration function and comprises alternatively or additionally a nonwoven layer.

A preseparator nonwoven can be arranged in particular at the raw side on the filter element, for example, glued thereto, or can be present at a predefined spacing to the filter element, wherein an arrangement directly on the filter element has the advantage that the preseparator nonwoven can be exchanged together with the filter element during service. Advantageously, the preseparator nonwoven has in addition water-separating and draining properties and is therefore capable of additionally protecting the filter element.

According to an advantageous further embodiment, it can be provided that the ambient air purification device comprises, upstream of the at least one filter element in flow direction, a water separator for separating rain water and/or splashing water. The water separator can preferably comprise a lamellar separator and/or a hydrophobic, in particular hydrophobically impregnated, separator layer and/or in particular closable flaps or lamellas. The water separator can in particular be switched on or positioned in the flow path as a function of a rain sensor signal and/or windshield wiper signal. In case of closable flaps or lamellas, they can be adjusted depending on the rain sensor signal/windshield wiper signal. The water separator can in particular be arranged upstream or downstream of the pre- or coarse separator. A windshield wiper signal, when coupling the ambient air purification device with the road vehicle, can be extracted without problems from a data bus of the vehicle and describes an operating parameter of the windshield wiper (e.g., on/off, wiper speed). Of course, tapping of the windshield wiper signal can also be realized differently, for example, purely electrically.

According to an advantageous further embodiment, it can be provided that at the ambient air purification device a mounting opening for the filter element is provided which is in particular arranged laterally, vertically or, in intended travel direction, in a mounting state at the rear. In this context, it is preferred that the ambient air purification device comprises holding means for the at least one filter element which prevent by form fit a movement of the filter element in travel direction in order to prevent a release of the filter element in case of braking and rear-ending situations. The holding means are preferably configured such that the opening cross section within the holding means is smaller than the cross section of the filter element transverse to the travel direction.

According to a further advantageous embodiment, it can be provided that the ambient air purification device comprises a drawer mechanism and/or releasable locking connections for mounting the filter element in the ambient air purification device. In this way, an easily serviceable ambient air purification device can be provided.

The filter element can be embodied as one piece or as multiple parts and in particular can comprise a plurality of filter units, in particular filter bellows and/or filter pockets. A plurality of sub filter elements can also be provided which are then joined to a filter element.

In a first further embodiment, the height of the at least one filter element can be in a range between 100 mm and 600 mm, preferably between 150 mm and 500 mm.

The parameters that have the greatest effect on the separation performance of the ambient air purification device are the height of the filter element and the flow resistance of the filter element which is determined significantly by the filter concept but not by the inflow speed. Therefore, a certain minimum height must be observed in order to achieve a satisfactory separation performance.

According to a further embodiment, it is proposed to embody the filter element with an inflow surface of at least 100 mm×250 mm, preferably at least 150 mm×500 mm. Alternatively or in addition, it can be provided that the volume of the at least one filter element amounts to at least 6.5 l, preferably at least 15 l. The net filter surface of the at least one filter element should be at least 3 m², preferably at least 7 m², most preferred at least 15 m². In case of use of a partially or fully synthetic filter medium instead of a cellulose-based one, smaller filter surfaces may also be sufficient.

The filter element, alternatively or additionally, may comprise a plurality of fold stabilization means which in an embodiment with folded filter bellows support the latter and are arranged at a lateral spacing of not more than 150 mm relative to each other. An embodiment of the filter element as a folded filter is preferred due to the reduced pressure loss in comparison to other configurations.

Such a support of the filter bellows by fold stabilization means meets two concerns: Firstly, the filter element due to the travel speed, even in the rear region, is subjected to a high impact pressure and, secondly, the filter element is exposed to wet conditions, not only by precipitation but also due to the actions when cleaning the vehicle, for example, with a high pressure cleaner.

Surprisingly, the aforementioned problems can be elegantly solved by supporting the folds of the filter bellows by fold stabilization means at a maximum spacing of 150 mm so that the filter element survives an inflow at Vmax (in case of direct inflow), e.g. 180 km/h, preferably >200 km/h, without being damaged, as well as that it cannot be damaged by external cleaning actions by high pressure cleaners. Without effective fold stabilization means, a filter element with classic bellows configuration in case of such mechanical action is at risk of compacting of the folds, i.e., a closure of the intermediate fold spaces, which leads to a sudden loss of filter surface and thus immediately causes a corresponding rise of the flow resistance and thus a corresponding drop of volume flow.

The range of the lateral spacing of the fold stabilization means in accordance with the invention of not more than 150 mm can advantageously be limited downwardly such that the spacing preferably is greater than 15 mm, preferably greater than 30 mm, because otherwise an unfavorable ratio of filter bellows regions covered by the fold stabilization means and free flow-through regions would be present.

Advantageously, a filter element with such fold stabilization means enables that an ambient air purification device provided therewith can be operated optionally without separate splashing water protection (flaps, rolling shutters or the like) because the filter element itself has such a great stability that a water impact action does not lead to damage of the filter element. The ambient air purification device comprises therefore only a minimal complexity and can be provided surprisingly inexpensively.

Various fold stabilization means are possible that fulfill this function.

In a particular embodiment, it can be provided that the fold stabilization means each extend parallel to each other, preferably in transverse fold direction. Other angular orientations are of course also possible, for example, diagonal. It is also possible to provide two groups of fold stabilization means that each extend parallel to each other and cross each other. A parallel extension has the advantage that it can be realized without problems by continuous manufacturing processes during the filter element manufacture. An arrangement of the fold stabilization means in transverse fold direction is in particular advantageous because in this case the smallest possible support length between two neighboring folds can be realized which leads to a particularly effective fold support.

In a further embodiment, it can be provided that the fold stabilization means are present at least at a clean air side of the filter element, preferably additionally at a raw air side of the filter element. With such an arrangement at least at the clean side, it is reliably prevented that the folds will compact under the aforementioned mechanical loads. An arrangement additionally at the raw side increases the load resilience further wherein however the greater contribution to filter element stiffness is provided by the clean-side fold stabilization means.

Moreover it can be provided that the filter medium has a bending stiffness of at least 1 Nm², preferably at least 2 Nm². This refers to an intrinsic bending stiffness of the filter medium, i.e., in an unprocessed/unfolded state.

According to yet another embodiment, the fold stabilization means can comprise at least an inner fold stabilization means that engages at least partially the intermediate fold spaces, preferably fills out the intermediate fold spaces. The inner fold stabilization means can be, for example, a continuous adhesive bead and/or an engaging stabilization comb. A Acontinuous adhesive bead@ is to be understood in the present case as an adhesive bead which, already prior to folding, is applied onto the flat filter medium and thus extends completely from the fold base to the fold tip after folding, i.e., is indeed continuous. As an alternative or in addition thereto, at least one outer fold stabilization means can be provided that is connected at least with respective neighboring fold tips. The outer fold stabilization means can comprises at least one adhesive bead connected at least with the fold tips, at least one thread connected at least with the fold tips and/or at least one stabilization band or rib and/or at least one support grid. The outer fold stabilization means can moreover be connected by material fusion with the fold tips which contributes to an optimal force introduction from the fold tips into the outer fold stabilization means. Such a material-fused connection, for example, can be provided by welding the outer fold stabilization means to the filter bellows, in particular the fold tips, in particular by hot plate welding. In contrast to the inner fold stabilization means, the adhesive bead of the outer fold stabilization means is not a continuous adhesive bead but one that is connected surf icially with the fold tips.

The adhesive beads of the inner and/or outer fold stabilization means can have a width in a range of 0.5 mm to 12 mm, preferably 1 mm to 8 mm. In a particular embodiment, the folds of the filter bellows are Ablocked@ so that the fold spacing corresponds to approximately twice the width of the continuous adhesive beads (as inner fold stabilization means). A hot melt is conceivable as material for the adhesive beads, for example.

Alternatively or additionally, the filter medium of the filter element of the ambient air purification device may comprise one or several embossment lines that preferably extend in transverse fold direction. By means of such embossment lines, the stiffness of the folds of the filter bellows is additionally increased by an increase of the geometrical moment of inertia, which additionally contributes to preventing a collapse/compacting of the folds under the action of pressure.

In a particularly preferred embodiment, it can be provided that the filter element of the ambient air purification device comprises a collapse pressure strength of at least 15 mbar, preferably at least 25 mbar.

The at least one filter element can comprise a single-layer or multi-layer filter medium that has at least a particle filter layer, in particular a cellulose layer and/or a synthetic fiber layer, in particular a synthetic fiber nonwoven, and/or at least a gas filtration layer, in particular with an active carbon bulk material as an active material. The gas filtration layer can be provided with corresponding active materials which enable an adsorption/absorption of various health-hazardous gases from the ambient air, for example, ozone, sulfur dioxide, nitrogen oxides, and carbon monoxide. For this purpose, different active materials can also be used. The active carbon can also be impregnated in order to improve the separation of certain gases, for example, by use of copper or copper compounds in order to increase the absorption of NO_(x). By use of such an active carbon bulk material, the absorption performance of the employed filter element(s) can be adjusted such that the ambient air purification device absorbs approximately as much NO_(x) as is emitted by the road vehicle to which it is mounted. Preferably, catalytic active carbon can be used that, for example, is useable for conversion of nitrogen oxide to less harmful substances, for example, nitrogen and carbon dioxide.

The ambient air purification device should exhibit a pressure loss for inflow with air at standard conditions with 1.5 m/s of at most 200 Pa, preferably at 2.5 m/s of at most 250 Pa.

Moreover, the at least one filter element can be a folded filter element that can embodied to be installed such that its folds extend in the longitudinal vehicle direction or in vertical vehicle direction. The concrete fold orientation depends however on the flow direction. In case of flow in the mounted state in the vertical vehicle direction, a fold orientation along the vertical vehicle direction is correspondingly advantageous because, in this way, the inflow into the fold pockets is optimal.

The fold heights of the filter element amount advantageously to at least 100 mm, particularly advantageously more than 200 mm. In this way, a comparatively large filter surface can be accommodated in a compact installation space. Alternatively, the filter element can be a so-called compact element. ACompact element@ is to be understood as a filter element that comprises a filter medium body which is comprised of alternatingly wound corrugated and flat layers of filter medium, wherein they are glued to each other across the surface. The flow channels which are formed by the corrugated layers are alternatingly closed off at the end faces, for example, by an adhesive plug.

Moreover, it can be provided that the filter element is a pocket filter element that comprises at least three filter pockets, preferably four or more filter pockets. Alternatively or additionally, also a V-filter element can be used that comprises at least three V-shaped filter units. Such filter element types are available on the market in the field of intake filters for gas turbines and/or HVAC systems in many size ranges.

Alternatively or additionally, the filter element can be a filter element that at least corresponds to the particle filter class M6 according to DIN EN 779.

Moreover, it can be provided that the filter element has a variable fold height, preferably a variable fold height across a vertical vehicle axis or viewed in the travel direction. By means of this, for example, an adaptation of the outer contour of the filter element to an installation space at the rear of the vehicle can be achieved and/or a shape matched to the flow pattern about the vehicle in the downstream region.

In one configuration, the ambient air purification device comprises at least one air conveying device for assisting the flow, in particular for a controlled assistance of the flow, for example but not limited to, when a vehicle is parked or at low travel speeds, in particular depending on the travel speed. The air conveying device comprises in particular an electrical connecting element that is connectable to the power supply of a road vehicle. The power supply of the road vehicle can be in particular a trailer coupling socket; the electrical connecting element a plug corresponding therewith.

Alternatively or additionally, the power supply can also be a photovoltaic power supply which is arranged on the ambient air purification device and/or a wind turbine that can be driven by the oncoming wind when driving.

The air conveying device can be an axial fan or an axial blower. The air conveying device can comprise in particular an electrical drive which is connectable electrically to the vehicle electrical system of the road vehicle. By means of the trailer coupling socket, a sufficiently large electrical power for driving the at least one air conveying device can be tapped in this context; for example, the air conveying device can comprise an electrical power of 120 W. Axial blowers or axial fans are preferably used as a result of their advantageously minimal installation dimensions viewed in axial direction; the invention is however not limited to this; radially or diagonally operating fluid flow engines are also encompassed by it. The invention encompasses expressly passive flow ambient air purification devices as well as active flow ambient air purification devices with at least one air conveying device.

The ambient air purification device according to the invention functions in one embodiment according to the principle of passive flow by means of the impact pressure which is generated by the travel speed. Since the problem of excessive air pollution primarily exists in metropolitan areas in which the travel speed is usually below 40 km/h, the pressure loss of the ambient air purification device should be so minimal that the latter is still flowed through at the impact pressures occurring at usual inner-city speeds. For example, the impact pressure at a travel speed of 30 km/h is approximately 40 Pa and at 40 km/h approximately 75 Pa.

A further aspect of the invention concerns a road vehicle, in particular a passenger car or truck, in particular light truck, in particular driven by an internal combustion engine and/or electric drive. The road vehicle comprises an ambient air purification device according to the invention which is embodied in particular for removing dusts, in particular particulate matter, and/or gases from the ambient air, wherein the ambient air purification device comprises at least one filter element and is arranged in an external region of the road vehicle. The ambient air purification device is fastened at the rear of the vehicle by means of a releasable coupling wherein the road vehicle comprises a vehicle-side coupling component which is releasably connectable with the corresponding mating coupling of the ambient air purification device.

The road vehicle can be, for example, a passenger car or bus or truck with or without a vehicle frame.

The features which have been disclosed in connection with the ambient air purification device according to the invention can be combined in any combination also with the vehicle according to the invention, and vice versa.

The advantages of such an arrangement have already been described in connection with the ambient air purification device according to the invention.

The vehicle-side coupling component can be a trailer coupling, in particular a ball mount coupling as it is conventional in passenger cars. A trailer coupling is rigidly connected to a car body or a frame of the road vehicle and is therefore particularly well suited to absorb also greater loads, such as the weight of the ambient air purification device as well as fluid-dynamical loads, while an attachment/removal is possible with a few manipulations and can be performed even by a technical layperson without problems.

As a side effect, the ambient air purification device when arranged at the rear of the vehicle, i.e., behind the rear axle of a vehicle, is also reducing thrown rock damage and contributes to safety of the following vehicles. Due to the very simple construction and simple as well as quick installation of the ambient air purification device according to the invention, existing vehicle fleets can also be retrofitted therewith without problem.

The arrangement of the ambient air purification device according to the invention at the rear has the advantage that the flow resistance of the vehicle is increased only minimally while superstructures and/or attachments as they are known from the prior art entail a significant deterioration of the flow pattern about the vehicle. That the effect is rather minimal, is known from rear bicycle carriers or rear game carriers which only affect flow in the downstream region and therefore have significantly reduced flow-dynamical effects in comparison to a roof carrier.

According to a further embodiment, the at least one filter element of the ambient air purification device can be flowed through in the longitudinal vehicle direction and/or at least partially perpendicular to this direction, in particular in vertical vehicle direction from bottom to top. Alternatively or in addition, the flow through the ambient air purification device as a whole can be realized at least partially, preferably completely, in the vertical vehicle direction.

A flow from bottom to top has the advantage that the ambient air can be sucked in from the bottom region which, in comparison to layers of air above, in general is significantly more strongly loaded with pollutants, in particular particulate matter. This correlation is characterized by the so-called wake factor; this is a conversion factor which is obtained by a comparison of air quality measurements at stationary measuring stations with vehicle-near measurements at the ground. Based thereon, loading at the vehicle-near ground is higher by approximately a factor 2 than the measured values at the stationary measuring stations.

It is therefore preferred to arrange the ambient air purification device or its air inlet at a level as low as possible. In this way, the absolute particle quantity separated per traveled distance can be increased.

Moreover, it is preferred to arrange the ambient air purification device external to the car body of the vehicle. The shape of a vehicle is usually designed such that the flow can be guided about the vehicle in the best possible way. An arrangement of the ambient air purification device external to the car body can therefore contribute to optimizing the air quantity which can be passed through the ambient air purification device, in particular when the ambient air purification device or flow deflecting means are designed, as preferred, so that a portion of the air which is flowing about the vehicle can be deflected in a targeted fashion to the ambient air purification device.

Preferably, a free outflow zone is provided in travel direction downstream of the ambient air purification device. As an alternative to the flow direction Ain longitudinal vehicle direction@, the flow can also be referred to as Ahorizontal@ when the vehicle is standing on a horizontal support. In a beneficial arrangement of inlet and outlet openings for the air to be purified and a corresponding conduit of the air to be purified within the ambient air purification device, a flow control within the ambient air purification device at least partially perpendicular to the travel direction is also possible, of course.

AFree outflow zone@ means that in the flow direction downstream of the filter element of the ambient air purification device no installations which would impede the flow are present because the purely passive flow, according to some embodiments, would otherwise be disturbed by the increased pressure loss.

Moreover, the ambient air purification device can extend across a significant portion of a vehicle width at the rear of the vehicle. Preferably, the ambient air purification device extends across at least 30% of the vehicle width, more preferred across at least 40%. Preferably, an embodiment is such that the ambient air purification device extends at least across a width that corresponds to the spacing between two wheels of a vehicle axle.

It can furthermore be provided that the ambient air purification device comprises at least one rear lighting system, in particular all lighting systems (brake light, turn signal etc.) to be provided at the rear region based on regulatory requirements for public roads so that the rear lighting systems existing at the rear region of the road vehicle are replicated at least when partially covered. For power supply and signal supply of these lighting systems, a trailer coupling socket existing in the rear region of the road vehicle can be advantageously used.

In order to provide an impression of the excellent efficiency of such a vehicle according to the invention with ambient air purification device, flow simulations based on the following parameters were performed:

-   -   particle concentration in the test air with 25Φg/m; PM2.5,         50Φg/m; PM10,     -   height of the filter element 300 mm,     -   width of the filter element 600 mm,     -   degree of separation for PM2.5 and PM10 80%, cellulose-based         filter medium, thickness of the filter medium 0.7 mm, air         permeability 700 l/m²s with 9 m² effective filter surface.         Based on these assumptions, the result is that such a filter         element for passive flow separates more PM10 particles than         generated by the diesel engine. In this context, a PM10 emission         of 6 mg/km was assumed. Therefore, the emissions can be reduced         to the value of an electric vehicle. By installation of active         components, for example, fans, the separation performance at low         speeds can be improved still.

Finally, a filter element for the ambient air purification device according to the invention is claimed. The features and advantages which have been mentioned in relation to the road vehicle according to the invention and to the ambient air purification device according to the invention are transferable thereon in any combination.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and expedient embodiments can be taken from the additional claims, the figure description, and the drawings.

FIG. 1 shows in schematic illustration a road vehicle according to the invention in a side view.

FIG. 2 shows in schematic illustration a first embodiment of an ambient air purification device preferably for the road vehicle in FIG. 1.

FIG. 3 shows in schematic illustration a second embodiment of an ambient air purification device preferably for the road vehicle in FIG. 1.

FIGS. 4 and 5 show a schematic illustration of an inflow-side region of the ambient air purification device, respectively

FIG. 6 shows an isometric illustration of a modification for an ambient air purification device according to the invention.

FIG. 7 shows an isometric illustration of a further modification for an ambient air purification device according to the invention.

FIG. 8 shows an isometric illustration of a pocket filter as it can be used in the ambient air purification device according to the invention.

FIG. 9 shows an isometric illustration of a V-filter as it can be used in the ambient air purification device according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows in schematic illustration a road vehicle according to the invention in a side view in which the ambient air purification device 1009 is arranged in the rear region of the road vehicle 1 by means of a releasable coupling 1030 wherein a trailer coupling 1031, for example, a ball mount coupling, of the road vehicle 1 is used at which the ambient air purification device 1009 by means of a mating coupling 1032 encompassed by it is preferably rigidly connected. The mating coupling 1032 of the ambient air purification device 1009 which is attached to the trailer coupling 1031 of the road vehicle, can be advantageously a friction-fit device engaging the ball mount by means of which the weight of the ambient air purification device as well as the flow-dynamical force actions can be absorbed without problem. Of course, the mating coupling 1032 can also be matched in another way at the trailer coupling 1031 and/or can have additional stays, for example, for supporting moments.

The afore described arrangement of the ambient air purification device 1009 at a trailer coupling 1031 has the advantage that it can be attached or detached by the end user with a few manipulations. When the ambient air is momentarily not loaded with particulate matter and/or harmful gases and/or for traveling in low-load regions, vacation trips etc., he can simply decouple the ambient air purification device 1009 while he can simply selectively attach the ambient air purification device 1009 again for traveling in highly loaded metropolitan areas and/or zones with bans on driving for high emission vehicles.

FIG. 2 shows in detail view a detail of FIG. 1 with a schematic illustration of an embodiment of an ambient air purification device 1009. The ambient air purification device 1009, as shown, can be embodied L-shaped with a first vertical leg which is flowed through by the incoming flow, whose direction 1123 is schematically indicated, from bottom to top and an adjoining second leg which is projecting away from the road vehicle horizontally. In the first leg, there are optionally arrangeable, configured to be sequentially flowed through from bottom to top, an inlet 1111 that comprises, for example, means for preventing entry of animals such as rodents, birds or the like, for example, a grid; a further protection stage 1112 that, for example, a thrown rock protection or a water separator, for example, comprising grids, baffle plates or deflector plates or deflector flaps that are positioned or positionable at a slant; at least one blower 1113 for enhancing the flow, in particular at low travel speeds, which preferably can be controlled depending on the travel speed, in particular in such a way that the rotary speed decreases with increasing travel speed; at least one guiding system 1114 for guiding the flow within the L-shaped housing; a filter element 1116 that, as shown, is preferably positioned at a slant for separation of particles such as particulate matter; a moisture sensor 1117, in particular for control of a movable water separator depending on the sensor signal; an outlet 1118 that, for example, comprises means for preventing entry of animals such as rodents, birds or the like, for example, a grid. In order to achieve a better utilization of the flow exiting from underneath the vehicle bottom, an inflow-side guide vane or a flow deflector 1119 can be arranged at the inlet 1111, in particular at its side facing away from the vehicle. The ambient air purification device 1009 can comprise at least one further sensor 1020 in its interior which preferably is arranged at the filter element 1116 or is enclosed by it and, for example, can measure moisture, particle or harmful gas concentration, pressure or pressure loss and report to an evaluation unit.

FIG. 3 shows in detail view a second embodiment as an alternative to FIG. 2 of an ambient air purification device 1010 and differs from the latter substantially in that the ambient air purification device 1010 has no L-shaped configuration but is substantially of a parallelepipedal shape and preferably can be flowed through from bottom to top. Same features are provided with same reference characters. The outlet 1118 in this embodiment is preferably at the end face of the housing 1115 which is facing away from the vehicle, further preferred, as shown, in its upper region. Flow from bottom to top has the decisive advantage that the particulate matter is sucked in where the greatest concentration is existing, i.e., in the ground-near region.

FIGS. 4 and 5 show a schematic illustration of a possible configuration of an inflow-side region of an ambient air purification device 1009, 1010 according to the invention. As a protective stage 1112, here preferably one or several motor-actuated means for preventing entry of animals such as rodents, birds or the like is encompassed, for example, a grid.

FIG. 6 shows an isometric illustration of a modification 1017 for an ambient air purification device 1009, 1010, 1017, 1018 according to the invention. According to this modification, the housing 1115 comprises a servicing opening with a closable servicing flap 1122 that permits an exchange of the filter element 1116. In ambient air purification devices which are configured for inflow at the front, at the bottom or at the top, an arrangement of the servicing flap 1122 at a wall of the housing 1115 which in travel direction is laterally arranged is possible and advantageous for servicing, for example, in the embodiment of FIG. 3. In the embodiment illustrated in FIG. 2, an arrangement of the servicing flap 1122 at an upper wall of the housing 1115, facing away from the road, is conceivable or advantageous. Moreover, an arrangement of the servicing flap 1122 at a front wall of the housing 1115, facing in travel direction, is conceivable or advantageous. In the embodiment illustrated in FIG. 3, an arrangement of the servicing flap 1122 at the rear wall of the housing 1115 which is facing opposite to the travel direction is moreover conceivable or advantageous.

FIG. 7 shows an isometric illustration of a further modification 1018 for an ambient air purification device 1009, 1010, 1017, 1018 in accordance with the invention. Here, as a protective stage 1112, an inflow-side first motor-driven rolling shutter 1124 and/or a second motor-driven rolling shutter 1125 is arranged in the housing 1115 which can close off inlet 1111 or outlet 1118. As in case of the aforementioned flaps, the control of these rolling shutters or flaps is preferably designed such that the rolling shutters or flaps are closed or will be closed when the vehicle is parked and/or beginning at a predetermined flow speed (travel speed), for example, 100 km/h, or in case of rain, snow or other temporary water introduction (as in a car wash, when actuating the windshield wiper device or the like). A functional connection with the modification illustrated in FIG. 6 is conceivable in such a way that the servicing flap 1122 can be opened only when the flaps or rolling shutters are open wherein the flaps or rolling shutters (i.e., more generally: the inlet 1111 and the outlet 1118) are respectively closed when the vehicle is not in operation and are open when the vehicle is in operation. Of course, the aforementioned functions are also controllable independent from each other, dependent on the operating state of the vehicle.

In FIG. 8, schematically a pocket filter element 100, 101 is illustrated as it can be used in the ambient air purification device 1009, 1010, 1017, 1018 according to the invention. The pocket filter element 100, 101 has a circumferentially extending rectangular frame 11 to which a plurality of, here eight, filter pockets 15 are attached. The filter pockets 15 are comprised of a suitable filter medium and are formed by sewing from the filter medium. Suitably, the pocket filter element is to be arranged such in the ambient air purification device 1009, 1010, 1017, 1018 that the filter pockets 15 with their hollow spaces 12, which form the respective inflow sides, are facing forwardly in travel direction. In order to prevent that the filter pockets 15 blow open too strongly by the inflow, oppositely positioned flat filter medium sections can be sown together by means of a suitable thread length. In other respects, the configuration of such filter elements is known to a person of skill in the art. Pocket filter elements are available on the market in a plurality of dimensions, for example, in the field of intake filters for gas turbines or the HVAC field. The illustrated pocket filter element 100, 101 has the dimensions 287 mm×592 mm×365 mm.

Moreover, in FIG. 9 a V-filter element 100, 101 is illustrated that comprises four filter units, arranged in a V-shape relative to each, which are formed by two flat filter elements 13, respectively, wherein the flat filter elements 13, for example, comprise a folded filter bellows. The illustrated V-filter element 100, 101 comprises therefore eight flat filter elements 13. The V-filter element 100, 101 comprises a frame 11 to which the V-shaped filter units are attached. At the bottom side which is facing away from the frame 11, two flat filter elements each that form a V-shaped filter unit are fluid-tightly connected to each other, respectively. The lateral surfaces which delimit the AV@ are each fluid-tightly closed off by a flat cover 14. For installation, the remarks in relation to FIG. 8 apply: The V-filter element 100, 101 is suitably inserted into the ambient air purification device 1009, 1010, 1017, 1018 such that the hollow spaces 12 face the inflow side, i.e., in the travel direction upon installation in the road vehicle 1 according to the invention. The dimensions of the V-filter element amount to 287 mm×592 mm×300 mm. The fold heights of the respective flat filter elements 13 amount to 25 mm in the illustrated embodiment.

For the pocket filter element illustrated in FIG. 8 as well as for the V-filter element illustrated in FIG. 9, it holds true that a suitable number thereof can be arranged adjacent to each other in order to provide an ambient air purification device 1009, 1010, 1017, 1018 with a sufficient width. Both variants can be used in the afore described embodiments of road vehicles or ambient air filter devices 1009, 1010, 1017, 1018.

As filter materials, fully synthetic nonwovens, glass fiber or cellulose media as well as combinations thereof can be used which in addition may comprise an electret action or can be accordingly furnished in order to achieve a good ratio of pressure loss and separation performance. Preferably, these media have hydrophobic properties and are distinguished by a good water stability. Also a filter medium can be used that completely consists of cellulose. The preferred bursting pressure of the filter elements should be in particular above 500 Pa, preferably above 1,000 Pa. The preferred dust capacity of the filter elements amounts to preferably at least 300 g, preferably more than 700 g. 

What is claimed is:
 1. An ambient air purification device for a road vehicle, wherein the ambient air purification device is configured to remove dust, particulate matter, and/or gases from ambient air, wherein the ambient air purification device comprises one or more filter elements, wherein the ambient air purification device is configured to attach in an external region to a vehicle rear of the road vehicle by a releasable coupling, wherein the ambient air purification device comprises at least one mating coupling of the releasable coupling, wherein the at least one mating coupling is configured to couple to a vehicle-side coupling component of the releasable coupling.
 2. The ambient air purification device according to claim 1, wherein the mating coupling comprises a trailer coupling.
 3. The ambient air purification device according to claim 2, wherein the trailer coupling is configured to attach to a ball mount coupling of the road vehicle.
 4. The ambient air purification device according to claim 1, wherein the mating coupling comprises a hatchback carrier device comprising at least one fastening element connectable to a vehicle door or a vehicle lid.
 5. The ambient air purification device according to claim 4, wherein the at least one fastening element is selected from the group consisting of a hook element, a magnetic mating coupling element, and a suction cup.
 6. The ambient air purification device according to claim 1, further comprising at least one receiving housing comprising at least an inlet opening and an outlet opening, wherein the one or more filter elements are received in the at least one receiving housing, wherein the at least one receiving housing is configured to connect by the mating coupling to the road vehicle.
 7. The ambient air purification device according to claim 1, wherein the ambient air purification device comprises two or more of the filter elements, wherein the two or more of the filter elements are arranged adjacent to each other in a transverse vehicle direction or in a vertical vehicle direction.
 8. The ambient air purification device according to claim 1, further comprising at least one flow deflector arranged at a lower edge of the ambient air purification device, wherein the lower edge is arranged in a travel direction of the road vehicle to the rear of the ambient air purification device and extends in a transverse vehicle direction.
 9. The ambient air purification device according to claim 1, further comprising a pre- or coarse separator arranged upstream of the one or more filter elements in a flow direction of the ambient air through the ambient air purification device, wherein the pre- or coarse separator is selected from the group consisting of a separator grid, a separator net, a baffle plate, and a preseparator nonwoven.
 10. The ambient air purification device according to claim 1, further comprising a water separator arranged upstream of the one or more filter elements in a flow direction of the ambient air through the ambient air purification device.
 11. The ambient air purification device according to claim 10, wherein the water separator comprises one or more separator elements selected from the group consisting of a lamellar separator, a hydrophobic separator layer, flaps, and lamellas
 12. The ambient air purification device according to claim 11, wherein the flaps and lamellas are configured to be closeable dependent on a rain sensor signal and/or a windshield wiper signal.
 13. The ambient air purification device according to claim 1, further comprising a mounting opening for the one or more filter elements, wherein the mounting opening is arranged laterally, vertically or to the rear of the ambient air purification device in a travel direction of the road vehicle.
 14. The ambient air purification device according to claim 1, further comprising a drawer mechanism or releasable locking connections for mounting the one or more filter elements.
 15. The ambient air purification device according to claim 1, wherein the one or more filter elements have one or more specifications selected from the group consisting of: an inflow surface of at least 100 mm×250 mm; a volume of at least 6.5 l; and a net filter surface that amounts to at least 3 m².
 16. The ambient air purification device according to claim 1, wherein the ambient air purification device comprises a pressure loss of at most 200 Pa at an inflow of the one or more filter elements with air at standard conditions at 1.5 m/s.
 17. The ambient air purification device according to claim 1, wherein the one or more filter elements are selected from the group consisting of a folded filter element comprising folds, a compact element, a pocket filter element, and a V-filter element.
 18. The ambient air purification device according to claim 17, wherein the folded filter element is arranged such that the folds extend in a longitudinal vehicle direction or a vertical vehicle direction, wherein a fold height of the folds amounts to at least 100 mm.
 19. The ambient air purification device according to claim 17, wherein the pocket filter element comprises at least three filter pockets.
 20. The ambient air purification device according to claim 17, wherein the V-filter element comprises at least three V-shaped filter units.
 21. The ambient air purification device according to claim 1, wherein the one or more filter elements corresponds at least to a particle filter class M6 according to DIN EN
 779. 22. The ambient air purification device according to claim 1, further comprising an air conveying device configured to assist in conveying air through the ambient air purification device, wherein the air conveying device comprises an electrical connecting element configured to connect to a power supply of the road vehicle.
 23. A road vehicle comprising: a vehicle rear; an ambient air purification device configured to remove dust, particulate matter, and/or gases from ambient air, wherein the ambient air purification device comprises one or more filter elements; a releasable coupling comprising a vehicle-side coupling component connected to the vehicle rear and at least one mating coupling connected to the air purification device; the ambient air purification device releasably connected to the vehicle rear in an external region of the road vehicle by coupling the at least one mating coupling to the vehicle-side coupling component.
 24. The road vehicle according to claim 23, wherein the vehicle-side coupling component is a trailer coupling.
 25. The road vehicle according to claim 24, wherein the trailer coupling is a ball mount coupling.
 26. The road vehicle according to claim 23, wherein the one or more filter elements of the ambient air purification device are flowed through in a longitudinal vehicle direction and at least partially perpendicular thereto in a vertical vehicle direction from bottom to top.
 27. The road vehicle according to claim 23, wherein the one or more filter elements of the ambient air purification device are flowed through in a longitudinal vehicle direction.
 28. The road vehicle according to claim 23, wherein the one or more filter elements of the ambient air purification device are flowed through at least partially in a vertical vehicle direction from bottom to top.
 29. The road vehicle according to claim 23, wherein the ambient air purification device extends in a transverse vehicle direction across at least 30% of a vehicle width.
 30. A filter element of an ambient air purification device according to claim
 1. 